1. Field of the Invention
This invention relates to automatic machine operations for recognition or identification of patterns, and, more particularly, the invention relates to a system to allow a character presence processor which searches for paths between character segments for character location to adapt to characters which ordinarily have vertical gaps therein and also have a weak stroke in certain characters which may appear to the character presence processor as a vertical path between character segments.
2. Description of the Prior Art
Automatic character recognition systems are usually either optical character recognition devices or magnetic ink character recognition devices or a combination thereof.
A problem which is common to both is to recognize the presence of a character at the rates present in industrial operations. Another problem is that certain characters have a tendency to have weak strokes and thus a single character may appear to the character presence detector as two characters. A weak stroke is a portion of a character which is closer to the background level than the surrounding portion of the character and, therefor, can appear as a gap in the character which the character presence processor can identify as a vertical path between character segments indicating that a character has ended and another begun. A similar problem develops with the introduction of certain fonts which have special characters. Some of these special characters have vertical gaps within the character itself and therefore a character presence processor which identifies and separates characters by finding a vertical gap between character segments identifies the portions of the character on either side of the vertical gap as a character. Thus, one character can be identified as two or more characters.
Recently, character recognition techniques have begun to incorporate a feature code generator which produces a multi-bit feature code characterizing unique relationships between line segments. As each row (or column) is scanned a feature code is produced representing the relationship between the character segments contained therein. Prior to the use of feature codes, character recognition systems utilized centering techniques to center a character in a matrix memory and then comparing the character in the matrix with a set of masks to recognize the character.
It has proved desirable to improve the reliability of character recognition at high speed rates and also to reduce the number of incorrect character decisions by providing a method and means of recognizing the presence of a weak stroke in a character and to expand the types of fonts and special characters which a feature code system can recognize. Because a character must be located, a character presence processor is usually employed to locate the character either in a memory or as shown herein within the output of a photo sensor array which is scanned at a high rate as compared with the movement of the array with respect to the characters to be read. Thus, a single character is scanned a number of times prior to passing out of the area being scanned by the array. The character presence processor locates the beginnings and endings of characters in order that it may control the utilization of the character codes produced from the feature codes.